Cyclo Air Brake Antifreeze & Dryer dissolves ice on contact to provide year round protection for air brake systems. It also has the added protection of a moisture remover. Just fill evaporator jar about 2/3 full of Cyclo Air Brake Antifreeze & Dryer. When compressor is working, air bubbles should be passing through the product. Check to ensure all connections are tight and filter cap and cover are in good condition.